1. Field of the Invention
The present invention relates to a novel silver halide color photographic light-sensitive material for recording images in color photography and a method of forming a color image utilizing the said light-sensitive material.
2. Description of the Related Art
Owing to remarkable development of light-sensitive materials utilizing silver halides, high-quantity color images are now easily obtainable. For example, according to ordinary color photography, a color print is obtained by the process comprising taking a photograph utilizing a color negative film, developing the film, and printing the image information, which is recorded in the color negative film, on color photographic paper in an optical way. Recently, this process has made remarkable progress, and large-scale, color development laboratories, in which a large quantity of color prints are produced in a very efficient way, have spread along with the so-called mini-laboratories which are now in shops and are designed to provide small-scale, relatively small-sized printer processing. Therefore, anybody can enjoy color photography easily.
The color photography, now in common use, reproduces color by the subtractive color process. Generally, a color negative film comprises a transmittable substrate and light-sensitive layers thereon utilizing a silver halide emulsion as a light-sensitive component having a sensitivity to the blue, green or red wavelength region of light, and a so-called color coupler capable of producing a yellow, magenta or cyan dye as a complementary hue of the sensitive wavelength region of the layer and thereby a colored image can be formed by the combination of the above light-sensitive layer capable of forming a dye. A color negative film, which has been exposed while taking a photograph, is developed in a color developer containing an aromatic primary amine developing agent. In this process, the developing agent develops, i.e., reduces the exposed silver halide grains, and the oxidation product of the developing agent, which are formed concurrently with the forgoing reduction, undergoes the coupling-reaction with the color coupler to form a dye. The silver (developed silver) generated by the color development and the unreacted (unexposed) silver halide are removed by means of a bleaching process and fixing process. This creates a color image on the color negative film. Consequently, a color photographic paper which comprises a reflective substrate and light-sensitive layers formed thereon having the same combinations of light-sensitive wave length region and hue to be produced as in the color negative film, is subjected to exposure through the developed negative film, and color-developing, bleaching and fixing processes in the same manner as in the patrone of the negative film to obtain a color print having a color image as a reproduction of an original scene thereon.
Although these systems for forming color prints are widely adopted at the present time, there is a growing demand for a simpler system. First reason for this is that expertise and skilled operation are necessary, due to the requirement of strict control of the composition and the temperature of the processing solution in a processing bath for the above-mentioned procedure consisting of color development, bleaching and fixing. Second reason for this is that closed equipment exclusively for the use in the developing process is often required, due to substances, such as a developing agent and an iron chelate compound, the discharge of which is regulated from the standpoint of environmental protection, contained as a bleaching agent in the processing solution. Third reason for this is that the currently available system does not perfectly fulfill the requirement for a rapid reproduction of image, as the above-mentioned developing process still requires a long time, although the time is shorted by the recent advance in technology.
Based on this background, there has been a strong demand for a simpler and more rapid system which does not utilize the developing agent and bleaching agent now in use for a conventional color image forming system and which accordingly minimizes the adverse effect on the environment.
In recent years, as an attempt to fulfill the above-mentioned requirements, many improved techniques have been proposed. For example, IS & T's 48th Annual Conference Proceedings, pp. 180, discloses a system in which the dye formed in the developing reaction is transferred to a mordant layer and thereafter stripping a light-sensitive material containing developed silver and unreacted silver halide from an image receiving material bearing the mordant layer to separate the developed silver and unreacted silver halide from an image formed by the dye without the use of a bleaching-fixing bath which has been indispensable to a conventional photographic process. However, this technique cannot perfectly solve the environmental problems, because it still needs a developing process by use of a processing bath containing a developing agent.
Fuji Photo Film Co., Ltd. has proposed a Pictrography System which dispenses with a processing solution containing a developing agent. In this system, a small amount of water is supplied to a light-sensitive material containing a base precursor which reacts with water to generate a base. The light-sensitive material and an image receiving material are placed face to face and heated to promote the developing reaction. This system does not use the aforementioned processing bath and, in this regard, is advantageous with respect to environmental protection.
However, this system cannot be used for photographic recording materials, because, in this system, a formed dye is fixed in a dye-fixing layer and the fixed dye in the layer is viewed. Therefore, a photographic light-sensitive material and a method for forming color images which can be used in this system are greatly desired.
On the other hand, high sensitivity, graininess, storage life, and similar properties are required for silver halide emulsions used in a light-sensitive material from the standpoint of high image quality and toughness. Utilization of tabular grains as one form of sensitivity enhancement technology of silver halide emulsions is known. A process for preparation of tabular grains used in conventional liquid development photographic systems and utilization technologies thereof are disclosed in U.S. Pat. Nos. 4,434,226, 4,439,520, 4,414,310, 4,433,048, 4,414,306 and 4,459,353, and Japanese Patent Application Laid-Open (JP-A) Nos. 59-99433, 62-209445 and the like.
In Pictorography System aforementioned, a previously prepared dye is contained in a light-sensitive material and the dye is transferred to an image receiving material to form colored images thereon. However, with this system, a level of resolution equal to that required of photographic material cannot be obtained. From the view point of resolution, a system in which an image is formed not on the image receiving material but on the light-sensitive material is advantageous.
Further, since the previously prepared dye is contained in the light-sensitive material, part of the exposed light is absorbed by the dye (filter effect), which is disadvantageous in terms of sensitivity and results in the sensitivity enhancement required for light-sensitive materials not being obtained. From the view point of sensitivity, the system in which a coupler capable of forming a dye at the time of development by a coupling reaction with an oxidation product of a developing agent is contained in the light-sensitive material is more advantageous than the system in which a dye has been previously formed.
However, as a result of study of the application of a silver halide tabular grain emulsion for the color photographic light-sensitive material containing a coupler and a color developing agent, it was found that the sensitivity of such a light-sensitive material significantly increases during storage. It was also found that the variation in sensitivity at the time of development of the color photographic light-sensitive material containing the silver halide tabular grain emulsion and the color developing agent is larger than the variation in sensitivity at the time of development of conventional light-sensitive materials which development is effected by a processing bath containing a color developing agent.
When the light-sensitive material the sensitivity of which has increased with time after preparation of product is photographed by a camera which determines exposure time automatically, any negative image answering the photographic purpose can not be obtained due to over-exposure.